Wrocław builds a new system, regenerates an old one Continuation of the EU Project

Piotr Kosz, Steinzeug-Keramo Sp. z o.o.

MPWik Sp. Z o.o. is the name of the municipal water-supply and sewage-disposal company of the city of Wrocław (Breslau) with a population of 630,000 inhabitants, also serving some of the surrounding towns and villages. The company manages and operates a water-supply network about 2,000 km in length and a sewage system of around 1,420 km for the disposal of wastewater. Obsolete pipelines – the oldest ones date back to the year 1850 – and the development of housing areas around the edges of the city have made it necessary to replace and expand many sections of the sewage network in recent years.

Open and trenchless

Between 2009 and 2014, three engineering offices contracted by MPWik Wrocław devoted their efforts to planning the new construction of a sewage network with a total length of 93 km and to the regeneration of a further 6.6 km of sewage pipes. The subsoil conditions – alternating strata of sand, clayey sand, gravel, and clay, in some cases below the groundwater table – posed no major problems for the installation of the pipes in the open-trench method or using trenchless construction when it came to overcoming obstacles. The depth of the installation operations varied between 1.00 and 6.20 meters. The vitrified clay pipes installed in the open-trench method were of the DN 150 to DN 300 dimensions, while vitrified clay jacking pipes of the dimensions DN 150 to DN 400 were used for the trenchless method (see table).

Experienced and cost-efficient

Based on experience and taking cost-efficiency aspects into consideration, the responsible engineers didn’t need long to opt for pipe systems made of vitrified clay: for them the decisive criteria were the long service life, the high resistance to abrasion, and the pipes’ resistance to chemical impact, and last but not least the targeted depreciation period of 80 to 100 years.

Wrocław is receiving 24 million euros of the total investment amount of 53 million euros from EU regional development funds, leaving a tab of 29 million euros for MPWik and its customers. Money well invested – for many generations to come.